We release several new antibodies. These are a new mouse antibody to muscleblind like protein 1, MCA-1H1, and several to Calbindin, made in both mouse MCA-5A9, MCA-4H7 and chicken CPCA-Calb (page in preparation). We also continue to develop a better understanding of all of our current reagents. For example, we previously made antibodies to the abundant cytoplasmic enzyme Aldolase C, both monoclonal and polyclonal. A potential problem with antibodies to this protein is cross-reactivity with the Aldolase A and B molecules which are very similar in amino acid sequence. Each Aldolase is 70-80% identical to the other two and the molecules have very similar molecular sizes on SDS-PAGE gels so one cannot distinguish which protein is being detected using western blotting. So we went to the trouble of expressing both human Aldolase A and B in order to test our panel of Aldolase C antibodies. We found that two of our monoclonals MCA-1A1 and MCA-4A9 were absolutely specific for Aldolase C, while a third MCA-E9 recognized all three Aldolases. We suspected that this might be the case since MCA-1A1 and MCA-4A9 were made against the C and N-terminal peptides respectively, which are the least conserved parts of the three Aldolases. In contrast, MCA-E9 was made against the intact human recombinant protein, and we now know that the epitope does not include either the N or C terminal sequences. Our rabbit polyclonal antibody to Aldolase C, RPCA-AldC, (page in preparation) not surprisingly, also recognizes all three Aldolase enzymes. Since Aldolases are abundant enzymes found in many tissues, we believe that using antibodies such as MCA-E9 and RPCA-AldC, which recognize all three, might be particularly useful as a western blotting standard, similar to our pan-specific actin antibody MCA-5J11.